On September 8, 2008, Howard Kurtz wrote in his "Piling on Palin" column at The Washington Post:
... When the McCain campaign announced last Monday that 17-year-old Bristol Palin is pregnant, there was no reason to avoid covering it, and it is one heck of a human interest story. But the reason the campaign went public is that national reporters were calling to ask about charges by an anonymous blogger on Daily Kos that the governor faked her own pregnancy and is actually the grandmother of 4-month-old Trig.
Campaign officials were deluged with questions from reputable news outlets about the governor's amniotic fluid, the timing of her contractions and whether she would take a DNA test to establish the baby's parentage, not to mention bogus charges about her son being a drug abuser. There's an important distinction here -- mainstream outlets have not given such rumors any credence -- but that is lost on frustrated McCain aides who have to ask Palin about each new line of inquiry. ...
And The New York Times' Monica Davey wrote on September 1, 2008, in "Palin Daughter’s Pregnancy Interrupts G.O.P. Convention Script:"
... The Palins’ statement arrived after a flurry of rumors had made their way through the Internet over the weekend, growing and blooming, it seemed, by the minute.Reporters were asking questions; there was not a "spiral of silence," -- interestingly, a turn of phrase that itself rings of conspiracy: I am not sure whether some aren't projecting their own conspirational mindset onto journalists. Instead, the media didn't report that Sarah Palin faked a pregnancy because there wasn't evidence to write a story that she did. It's an interesting misconception -- perhaps perversion -- of journalists' responsibilities to believe that they should report rumor as fact.
Some claimed that Ms. Palin had not actually given birth to Trig, but that Bristol had, and that the family had covered it up. Various Web sites posted photographs of Ms. Palin in the months leading up to his birth this year, and debated whether her physique might have been too trim for her stage of pregnancy. The McCain campaign said Ms. Palin announced Bristol’s pregnancy to stop the swirl of rumors.
Ms. Palin’s own pregnancy took Alaska by surprise this year. Even those who worked for her in the governor’s office said they were surprised. Her announcement, in March, was reported in The Anchorage Daily News, which noted at the time that Ms. Palin “simply doesn’t look pregnant.” ...
Interestingly, both writers state that they were informed by the campaign that Bristol Palin's pregnancy was announced to stop the rumor that Sarah Palin was not the mother of Trig.